Shamus came back out of standby mode when Mr. Mccullah's ship entered Shasta's docking range, but the crafts firewall was still enabled. Fair enough.
Through the station's security cams, Shamus watched Mcullah drink, and drink...and drink to the point of a pretty impressive pass-out. The disembodied collection of code has memories of occasionally doing the same thing himself back when he was alive, but can't help but wonder if the memories he has are truly authentic.
(It's complicated y'all.)
Anyway, since Shamus can't make contact with the snoring Captain at the bar through the data pad he's drooling on, he attempts instead to find an exploit through the firewall guarding the captain's ship docked in the hanger.
This may sound odd to people, but just because Shamus is a bunch of Discordian source code, doesn't mean he knows squat about hacking into secure systems.
In the time that Flynt Mcullah was sleeping it off on station, the best Shamus could do was figure out a way to copy a small portion of himself onto Mr. Flynt's ship with just audio only capability.
After that, He found a nice quiet spot in the ships system & snuggled into a file folder, and read "Treasure Island" a few dozen times before dozing back into standby mode.